The instant invention relates to a buckle chute folding system for paper documents and more particularly to apparatus for eliminating the shingling effect on documents as they change from the horizontal to vertical direction of travel and enter the nip of a pair of feed rollers associated with the buckle chute folding system.
Buckle chute paper folders employing folding rollers are well known. A sheet of paper is fed by a first pair of feed rollers into a buckle chute, which stops the forward progress of the paper sheet and causes a buckle to be formed. The buckle is then forced to enter the nip of a pair of folding rollers (one of which may be one of the feed rollers) which impart a crease in the buckle. The folding rollers then continue to feed the folder sheet toward a pair of exit rollers or another buckle chute for forming a second fold or inverting the document so that the top surface becomes the bottom surface and vice versa.
There is a problem with respect to accurately folding a stack of documents at one time since the paper path of the documents to be folded is such that the documents are guided along an angular path away from the normal path of travel constituting a substantially straight path through the apparatus. When the stack of documents is guided along such a diverted angular path, the outermost document of the stack travels a shorter (or longer) distance than the inside document when the stack is positively pushed or conveyed by cooperating pairs of feeding rollers. The result is that no two of the documents in the folded stack have exactly the same fold. This lack of uniform folding causes the folded stack to be unevenly folded, and in the case of varying folded sizes of documents, may result in some of the documents exceeding the size of the opened envelope into which the folded stack is to be inserted, thereby preventing insertion.
In dealing with the aforementioned problem, which results in a shingling effect on the documents prior to their being folded, the prior art has introduced the use of a free wheeling foam roller adjacent one of the first pair of feed rollers, generally the lower of the two feed rollers. Use of the free wheeling roller adjacent one of the first pair of feed rollers did prove helpful in reducing shingling, but did not eliminate shingling in all cases. The instant invention thus provides apparatus which results in the shingling effect being virtually eliminated in all applications in which collations of paper sheets are folded by a buckle chute folder.
Accordingly, the instant invention allows a collation of paper sheets to change from a horizontal to a vertical direction of travel prior to the collation being folded and prevents the documents from becoming shingled prior to their being folded.